   "Iterates across the supplied two dimensional matrix, returning a
   lazy sequence of 2-element vectors of the form `[matrix entry,
   neighbor-seq]`. Neighbors outside the matrix are reported as
-  nil. For example:
+  nil. 
 
+  Example usage:
     (def test-matrix [[:0 :1 :2 :3]
                       [:4 :5 :6 :7]
                       [:8 :9 :a :b]
                       [:c :d :e :f]])
 
     (first (neighbor-scan 1 test-matrix))
-    ;=> [:0 ((nil nil nil) (nil :1) (nil :4 :5))]"
-
+       => [:0 ((nil nil nil) (nil :1) (nil :4 :5))]"
   [num-neighbors mat]
   {:pre [(> (count mat)
             (inc (* 2 num-neighbors)))]}

           (apply concat)
           (filter (complement nil?))
           (apply f)))))


               (repeat (* 2 buffer-size) buf-row))))

(defn wipe-out
  "Accepts a nested collection and a sequence of keys, and returns a new
  collection generated by removing the value located at the position
  indicated by the supplied key sequence.

  Example usage:
    (def test-matrix [[0 1 2] [3 4 5]])
    (wipe-out test-matrix [1 2]) => [[0 1 2] [3 4]]"
  [coll [k & ks]]
  {:pre [(or (nil? k) (coll? coll))]}
  (if-not k
